Re: add --match argument to git-version-gen

[Jim Meyering]

Andy Wingo wrote:
> On Fri 06 Jul 2012 17:45, Jim Meyering <address@hidden> writes:
>
>> How about writing a function -- with description similar to the comments
>> you've added below -- and doing something like the following?
>> Then we should be able to avoid that duplication.
>>
>>     elif test "`git log -1 --pretty=format:x . 2>&1`" = x \
>>    -    && v=`git describe --abbrev=4 --match="$prefix*" HEAD 2>/dev/null \
>>    -          || git describe --abbrev=4 HEAD 2>/dev/null` \
>>    +    && v=`git_desc "$prefix" "$match"` \
>>         ...
>
> Good suggestion.  Attached.
...
> Subject: [PATCH] git-version-gen: add --match argument.
>
> * build-aux/git-version-gen (Options): Add --match argument.
>   (match):
>   (tag_sed_script):
>   (tarball_version_file): Protect against ambient values of these
>   variables.
>   (git_describe, massage_git_version): New helper functions.  Require a
>   match in the --match case, and otherwise have our previous behavior.
>
> Using --match can prevent a merge from e.g. a version 2 branch to a 3
> branch from causing the 3 branch to show a 2 version, if the 2 version
> tagged more recently than the 3 version.

Thanks.  We're almost there.

...
> -   --prefix           prefix of git tags (default 'v')
> +   --prefix     prefix of git tags to strip from version (default 'v')
> +   --match      pattern for git tags to match

Please mention that it's a "glob" pattern,
so people don't think it's a regexp.

> -   --help             display this help and exit
> -   --version          output version information and exit
> +   --help       display this help and exit
> +   --version    output version information and exit
>
...
> +function massage_git_version() {
> +    local v=$1

Using the "function" and "local" keywords would make this script
fail for some older shells.  I'd like to remain portable to those.

>      # Is this a new git that lists number of commits since the last
>      # tag or the previous older version that did not?
>      #   Newer: v6.10-77-g0f8faeb
> @@ -182,7 +176,44 @@ then
>
>      # Change the first '-' to a '.', so version-comparing tools work 
> properly.
>      # Remove the "g" in git describe's output string, to save a byte.
> -    v=`echo "$v" | sed 's/-/./;s/\(.*\)-g/\1-/'`;
> +    echo "$v" | sed 's/-/./;s/\(.*\)-g/\1-/'
> +}
> +
> +function git_describe() {
> +    local prefix=$1
> +    local match=$2
> +    local v
...

Oh, and your patch added at least one trailing blank.